The invention relates to methods and equipment for managing composite objects in a data processing system for a telecommunication network, such as in a telephone exchange.
Network management standards are nowadays largely based on object-oriented descriptions, though the prevailing standards do not require the use of this technique. Objects are data structures in a network management system, which describe the functions and state of a network component. An object is an element having certain attributes (“I am like this”) and certain operations (“I can do these things”). In the object-oriented approach, objects with the same data structure (attributes) and the same behaviour (operations) are grouped into a class. A specific implementation of an operation is called a method and each object is said to be an instance of its class. A typical object is, for example, a representation of a cross-connection device with certain attributes (cross-connections that are active) and certain methods (e.g. make a cross-connection and release a cross-connection). An example of object-based network management is disclosed in co-assigned patent application WO97/24837, which is incorporated herein by reference.
A ‘physical resource’ (of a network) is a tangible resource, such as a cable, port, channel. A ‘logical resource’ is typically a physical resource with some enhancements or added value, such as a cable group which is an arbitrary combination of cables, or a path which is a route across a network, utilising cables, ports and channels. However, the distinction between physical and logical resources is not essential for understanding or implementing the invention. They both belong to the category of real resources (or simply ‘resources’), as distinct from software classes (of software objects), which are used for modelling real (i.e. physical or logical) resource types. A resource type represents a set or group of substantially similar network resources, such as circuits or ports. A resource instance is an individual instantiation of a resource type, for example ‘circuit 1234’ or ‘port 2-21’. A software object is an instance of an object class.
A managed or manageable object (MO) refers to a software presentation of a network resource which is capable of sending notifications or measurements and/or which must be configured from a network management system (NMS).
Managed objects are typically implemented in several subsystems, such as:
in the network element (NE) proper;
on the element management layer (EML) of the network management system (NMS);
in a regional subsystem of the network management layer (NML) of the NMS;
in a network-wide subsystem of the NML of the NMS;
in the service management layer (SML) of the NMS;
in one or more planning systems.
The above list is for illustration rather than limitation; there may be other subsystems where manageable objects are stored, and some of these subsystems may not be present in every telecommunications system.
There are valid reasons in favour of storing a separate realization of an MO in each of these subsystems. For example, these subsystems operate on different aspects of a given MO. Especially when a new subsystem is being constructed, aspects relating to other subsystems are not known (yet). In addition, telecommunication systems have high availability requirements which are difficult to meet by a single realization accessed over data communication links.
A problem with the prior art object-management mechanism is that implementing, operating and maintaining multiple realizations of a single MO is resource-consuming and error-prone.